JP2002026075A - Method and device for recognition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for recognition which can properly recognize an object to be recognized even if the contrast changes with the surface property of the object to be recognized. SOLUTION: This device is equipped with a color image input means 1 which picks up a color image of the object to be recognized, a color-monochromatic image converting means 4 which converts a picked-up color image signal into a monochromatic image signal, a conversion reference generating means 5 which generates a conversion standard for converting the picked-up color image signal into the monochromatic image signal according to the object to be recognized and characteristics of an image pickup means, and a monochromatic image processing means 6 which recognizes the object by processing the monochromatic image signal; when the color image is picked up and converted into the monochromatic image, the conversion standard is adjusted according to the object to be recognized and the characteristics of the image pickup system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recognition method and apparatus suitably used for recognition of the position of a bare IC when performing flip-chip mounting in an IC assembly facility.

[0002]

2. Description of the Related Art A conventional IC position recognition device in an IC assembly facility will be described with reference to FIG.

In FIG. 4, 11 is a monochrome image input means, 12 is an illuminating means for illuminating necessary for imaging, 13 is a bare IC cut out from a wafer to be recognized,
Reference numeral 14 denotes a monochrome image processing unit.

When recognizing the position of the bare IC 13 at the time of assembly, the illuminating means 12 illuminates the bare IC 13, the monochrome image input means 11 takes in the image of the bare IC 13, and the monochrome image processing means 14 positions the IC pattern. Is detected, and the position of the bare IC 13 is recognized.

[0005]

The bare IC 1
A protective film is formed on the surface of No. 3, and the protective film is often transparent or brown. In particular, when the surface of the bare IC 13 having a transparent protective film is observed with an optical microscope, the color of the surface often looks largely different mainly due to the difference in the thickness of the protective film. This is because the optical path differs depending on the thickness. In addition, variations in the film formation and pattern etching under the protective film are also greatly affected.

When the bare IC 13 is imaged by the monochrome image input means 11 as described above, the bare IC
The luminance of the IC pattern may vary greatly depending on the thirteen lots. FIGS. 5A and 5B show an example in which the brightness of the IC pattern differs between lots. As shown in FIG. 5, the contrast of the IC
There is a problem that the contrast of the pattern may greatly differ depending on the portion, and the position of the bare IC 13 may not be recognized.

The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a recognition method and apparatus capable of appropriately performing recognition even when a change in contrast occurs due to the surface properties of a recognition target.

[0008]

SUMMARY OF THE INVENTION A recognition method according to the present invention includes a step of capturing a color image of a recognition target and a method of converting a color image signal captured according to the characteristics of the recognition target and an imaging system into a monochrome image signal. Creating a conversion criterion, converting the captured color image signal into a monochrome image signal, and processing the monochrome image signal to recognize the recognition target. By adjusting the conversion criterion according to the characteristics of the recognition target and the imaging system when converting the image into a monochrome image, it is possible to appropriately recognize even if the contrast changes due to the surface properties of the recognition target.

In particular, when the present invention is applied to a case where a recognition target is a bare IC having a protective film formed on a surface thereof and the position of the bare IC is recognized from the IC pattern, even if there is a change in the contrast of the IC pattern due to variations in film formation, etc. Can recognize the position of the IC.

Further, the recognition apparatus of the present invention converts a color image signal into a monochrome image signal according to the characteristics of the recognition object and the color image input means. A conversion reference creating unit for creating a conversion reference at the time, an image converting unit for converting a captured color image signal into a monochrome image signal, and an image processing unit for processing the monochrome image signal to recognize a recognition target The effect can be obtained by implementing the above method.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a bare IC recognition apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a color image input means;
Reference numeral 2 denotes a lighting unit, and reference numeral 3 denotes a bear IC to be recognized. Reference numeral 4 denotes a color / monochrome image conversion unit that converts a color image signal input from the color image input unit 1 into a monochrome image signal and outputs the monochrome image signal. Reference numeral 5 denotes a conversion reference creation unit that creates a reference for converting a color image signal into a monochrome image signal in the color / monochrome image conversion unit 4. Reference numeral 6 denotes a monochrome image processing unit that processes the monochrome image signal and recognizes the position of the bare IC 3 from the IC pattern of the bare IC 3.

Next, the operation will be described.
Is illuminated by the illumination means 2, and the color image of the bare IC 3 is taken in using the color image input means 1. Then, the color image is converted into a monochrome image by the color / monochrome image conversion means 4. At this time, the reference for converting the image by the color / monochrome image conversion unit 4 is created in advance by the conversion reference creation unit 5. The monochrome image converted by the color / monochrome image conversion means 4 is processed by the monochrome image processing means 6, and the position of the bare IC 3 is detected. Naturally, the conversion reference creating means 5 is necessary only at the time of initial setting of the apparatus, and is not necessary when actually detecting the position of the bare IC 3.

Next, the principle of creating a reference for converting the color image into a monochrome image will be described. As described in the prior art, the contrast of the IC pattern changes in a monochrome image mainly because the surface color looks largely different due to thickness variation of the transparent protective film of the bare IC 3. Assuming that only the wavelength shifts even if the surface color changes, and that the wavelength band does not change, the cause of the contrast fluctuation is mainly that the sensitivity of the image capturing system including the illumination differs depending on the color including illumination. It can be said. For example, when a halogen lamp is used as the illuminating means 2, the wavelength component of yellow becomes strong. The sensitivity of the camera as the color image input means 1 also differs depending on the wavelength. In a general CCD camera, the red color has higher sensitivity.

FIG. 2 shows the sensitivity characteristics of an image pickup system in which both the illumination luminance and the CCD sensitivity with respect to the wavelength are combined. In such an imaging system, when the surface color of the bare IC 3 changes, the contrast changes by the sensitivity characteristic. FIG. 3 shows a difference in luminance between a case where the surface color of the bare IC 3 is green and a case where the surface color is pink. In FIG. 3, the curve in the graph is the sensitivity characteristic of the imaging system in FIG. 2, and the area of the hatched portion is the brightness of each bare IC 3. Note that the horizontal length of the hatched portion in (a) and (b) is the wavelength band, and if the length is the same, the contrast is low because the luminance is low in the green bare IC 3, and the contrast is low in the peach bare IC 3. It can be said that the contrast is high because the luminance is high.

If it is assumed that the change in the contrast of the IC pattern depends only on the sensitivity characteristic of the color of the imaging system, the conversion reference creating means 5 corrects the color sensitivity characteristic of the imaging system by the color image input means 1 and the illumination means 2. By setting the reference in this way, even if the surface color of the bare IC 3 changes, it is possible to prevent a contrast change from occurring in the monochrome image obtained by the color / monochrome image conversion means 4.

It should be noted that the actual contrast change cannot be said to be only the sensitivity characteristic of the color of the imaging system. For example, bare IC
When the surface color of No. 3 changes, the wavelength band may change with the shift of the wavelength, and there are other factors such as the surface state of the lower layer. However, by measuring the correlation between the change in contrast and the surface color of the bare IC 3 and creating a reference by the conversion reference creating means 5, it is possible to suppress the contrast fluctuation.

As described above, the conversion reference creating means 5
Can correct the correlation between the characteristics of the brightness of the bare IC in the monochrome image including the color sensitivity characteristics of the imaging system and the surface color of the bare IC. Can be suppressed.

[0019]

According to the recognition method and apparatus of the present invention, a conversion reference for converting a color image signal captured into a monochrome image signal according to the recognition target and the characteristics of the imaging system as described above is created. Since the captured color image signal is converted into a monochrome image signal, and the monochrome image signal is processed to recognize the recognition target, when the color image is captured and converted into the monochrome image, the conversion reference is used as the recognition target and the recognition target. By making adjustments in accordance with the characteristics of the imaging system, it is possible to properly recognize even when the contrast changes due to the surface properties of the recognition target.

In particular, a bare IC having a protective film formed on its surface
When the bare IC position is recognized from the IC pattern, even if the surface color changes due to film formation variation or the like and the contrast of the IC pattern changes, the IC position can be reliably recognized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a recognition device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of sensitivity characteristics of an imaging system in which sensitivity characteristics of an illumination unit and an image input unit in the embodiment are combined.

FIG. 3 is an explanatory diagram of a difference in luminance when a bear IC color is green and pink.

FIG. 4 is a configuration diagram of a conventional recognition device.

FIG. 5 is an explanatory diagram of an example in which the luminance of an IC pattern differs between lots.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color image input means 2 Illumination means 3 Bear IC (recognition target) 4 Color / monochrome image conversion means 5 Conversion reference creation means 6 Monochrome image processing means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihisa Oido 1006 Oji Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. F term (reference) 5F044 PP03 PP13 PP17

Claims (3)

[Claims] 1. A step of imaging a recognition target with a color image, a step of creating a conversion reference for converting a color image signal captured according to the characteristics of the recognition target and an imaging system into a monochrome image signal, and A recognition method, comprising: converting a color image signal into a monochrome image signal; and processing the monochrome image signal to recognize a recognition target. 2. The recognition method according to claim 1, wherein the recognition target is a bare IC having a protective film formed on a surface thereof, and the position of the bare IC is recognized from the IC pattern. 3. A color image input means for picking up a recognition target as a color image, and a conversion reference for converting a color image signal picked up into a monochrome image signal according to the characteristics of the recognition target and the color image input means are created. A recognition apparatus comprising: a conversion reference creating unit; an image converting unit that converts a captured color image signal into a monochrome image signal; and an image processing unit that processes the monochrome image signal to recognize a recognition target.